Method for casting copper or equivalent metals



Jan. 24, 1933. w. F. EPPENSTEINER 1,894,982

METHOD FOR CASTING COPPER OR EQUIVALENT METALS Original Filed March 6, 1930 1: s ENVENTOR N V I By Aiiem'zsys Patented Jan. 24, 1933 UNITED STATES PATENT OFFICE WILLIAM I. EPPENSTEINER, F RAH'WAY, EW JERSEY, ASSIGNOR TO THE AMERICAN METAL COMPANY, LIMITED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK METHOD FOR CASTING COPPER 0R EQUIVALENT METALS Application filed March 6, 1980, Serial No. 438,591. Renewed February 12, 1932.

This invention relates to the casting of copper or other metals or alloys having substantially like properties, for the production of fiat cakes or other shapes.

In the production of high grade sheet copper or copper strips from electrolytically refined copper or copper of similar purity, the best results have been attained by pouring into upright water-cooled molds having a vertical casting cavity with parallel sides or sides closely approaching to parallelism, under such conditions that the cast metal is rapidly solidified and caused to shrink free from the walls of the casting cavity, so that it may be discharged therefrom by gravity. The practice of this method, however, involves certain dilficulties which the present invention is designed to overcome.

According to the present invention the cooling water (or other cooling medium) entering the mold is maintained at a tempera ture lying between approximate extremes of 160 to 212 Fahrenheit. For this purpose a water tank is provided having means for heating and for cooling the water therein, with pipes leading therefrom to the mold jackets and returmng from the latter to the tank and with apump for circulating the water with suitable rapidity. The apparatus for best performing this process is illustrated in the accompanying drawing, where-' Figure 1 is a side elevation, partly in vertical section.

Fig. 2 is a plan, partly in horizontal section.

Referring to these figures, A A. are molds of the character hereinbefore described, and T is a tank of suitable capacity in proporac tion to the number and size of the molds used.

L is the usual ladle for pouring the molten copper into the molds. A pipe 10 leads from V the tank T and connects with the inlet pipes C C, leading to the mold jackets. The outlet pipes D D from the mold jackets connect means for heating the water which may suitably be a steam inlet pipe 14: having a suitable valve. The tank also has a water inlet pipe 15 controlled by a suitable valve. The tank also preferably has an internal baflie lplate 16to cause an admixture of the water efore it fiows out through the pipe 10. For discharging excess vapor, the tank has an open top outlet 17 It may also have an overflow pipe 18 for discharging surplus water from the tank. The return pipe 11 may be tapped by a pipe 19 with a suitable valve by which excess of hot returning water may be delivered to a hot well or to waste.

On commencing the operation the tank T being filled with water, steam is admitted to heat the water to preferably about 190 to 200 Fahrenheit. Before starting the casting the pump 12 is started, which causes the water to circulate from the tank through the mold jackets and back. As many molds may be provided as is desired to give the required casting capacity; and these molds may be mounted on a revolving carrier, the metal being poured at one point in the travel of the mold, and the hardened cast cake may be delivered out at another point in its travel. The heat of the molten metal adds to the heat of the water in the mold jackets, so that the water returns to the tank at a much higher temperature. To control the temperature of the water leaving the tank to keep it at (say) 190 Fahrenheit, a part of the hot returning water is run to waste or cooled through coils and its place is taken by fresh cold water admitted through the pipe 15. The control may be accomplished by hand, a. thermometer 20 being provided to assist the operator; or thermostatic means may be provided for automatically controlling the temperature of the water.

For casting copper cakes or ingots weighing about 250 to 600 pounds, the cooling water entering the mold jackets should most efliciently have a temperature approximating 190 to 200 F. On leaving the jackets the water will have been heated to from about 210 to 220 F, approximately. Because of the heating efiect of the molten metal, it is necessary, in order to keep the temperature throu cavity as to insure the free discharge of thefrom rising too high, to circulate the water rapidity. It is desirable to-be able to vary the speed of the pump 12 in order that the temperature control maybe varied as circums'tances may change. In making larger or smaller castings the temperatures of the water on entering, and leaving the molds ma be varied as required.

he proper cooling of. the mold is im ortant to successful operation, and articu arly to castiiig at a rapid rate. If t e.cooling is insufli'cient, the cast copper as ithardens will not shrink rapidly enough to so far separate it from the inner walls of the casting cast cake or billet when the mold bottom is dropped open. If the water. is too cold, so that the cooling is too rapid, the exterior ortion of the casting is solidified and cause to contract too much in advance of the solidification of the interior portion, with the result that imperfect castings will be formed.

I am aware that it has been proposed to cast cop er and other metals in jacketed molds, t rough the jackets of which water is circulated to cool the mold, presumably by connecting to an ordinary service pipe sup-' plying water at temperatures approximating 50 to F, My experience has shown that the cooling of the mold by water entering at such a lowtemperature cannot produce cast-' ings of the high grade, uniform character throu bout the cake and perfect surface .require for the production of fiat cakes for rolling.

In the Patent No. 1,748,333, granted February 25, 1930, to United States Metals Refining Company, the water entering the mold 'ackets is heated to between 212 and 270 F.

1y experience has shown that for casting parallel-sided, flat cakes in vertical undivided molds, suchtemperatures for the entering waterare too high to produce the best results. Especially for the casting of large cakes, the liberation of heat from the molten metal is so great that the water, immediately after entering the mold jacket, becomes heated to a much higher degree, requiring a considerable pressure to avoid the vaporization of the water and the consequent impairment of the effective cooling of the water jackets, and having the result that the cast the mold jackets with considerable through. the mold-jackets a'hi awd d so that the temperature of the-water will raised only acomparativel few do ing its circulation throug the j attain successful results I introduce the water at much lower temperature than that set forth in the last named patent, andcirculate" dur- I ts. I To' it at much higher velocity, so that when entering at approximately 190. to 200 F. it will emerge at ap roximately 210 to 220F. To

accomplisht is with molds of difierentcv' pacities it-is essential to control the velocity of the circulating water with proper 'relation the rate of discharge of heat from the molten metal to the mold jackets. -The pressure upon the jwater in the mold jackets when its temperature exceeds 212 F. is maintained a by the frictional head imposed by the return pi 11 so that the displacement .of the circu atin water by-steam in the moldjacke'ts;

is avoi ed. p

I claim as my invention: I

1. Themethod of casting copper alent metals in a water-cooled mold having a vertical casting-cavity with substantially parallel walls which consists in cooling the mold by a constant and rapid circulation of water through its cooling passages, the water entering at temperatures approximating 190 to 200 Fahrenheit.

2 The method of claim 1, further characterlzed in that the water is circulated with, such rapidity that its temperature while flowing through the cooling passages is increased iiott exceeding approximately 20 Fahrenel a" 3. I

3. The method of casting copperor, alent metals in a water-cooled mold having a vertical casting cavity with substantially parallel walls, which consists in cooling the .moldby a constant and rapid circulation of hot water through'its cooling passages, the water being circulated with such rapidit that its temperature while flowing throng coolingpassages is increased not exceeding approximately 20- Fahrenheit.

In witness whereof, I have hereunto signed name.

WILLIAM F. EPPENSTEIITER. 

